Controller for compacting machines

ABSTRACT

A material compacting construction comprising a compacting means, a first drive for the compacting means, a feeding means, and a second drive for the feeding means. Control means are provided for varying the operation of the feeding means in accordance with the load applied to the drive for the compacting means. The control means includes means for sensing the load and a meter connected to the sensing means. When the meter records a limiting position, indicating that the load has increased or decreased to a limiting value, an electrical circuit associated with the meter is operated. This circuit in turn operates adjusting means for the drive of the feeding means whereby the rate of material fed to the compacting means is adjusted. This adjustment is calculated to maintain the energy level and product quality at desired values.

United States Patent [19] Harris [54] CONTROLLER FOR COMPACTING I MACHINES [75] Inventor: Leroy S. Harris, Rolling Meadows,

Ill.

[73] Assignee: K-G Industries, Inc., Rosemont, 111-.

[22] Filed: Oct. 12, 1972 [2]] Appl. No.: 296,821

3,674,397 7/1972 Harris 425/363 X 3,734,659 5/1973 Harris 425/237 X 3,734,663 5/1973 Holm 425/149 X l July 16, 1974 Primary Examiner-Robert L. Spicer, Jr. Attorney, Agent, .or Firm-McDougalLHersh & Scott [5 7] ABSTRACT A material compacting construction comprising a compacting means, a first drive for the compacting means, a feeding means, and a second drive for the feeding means. Control means are provided for varying the operation of the feeding means in accordance with the load applied to the drive for the compacting means. The control means includes means for sensing the load and a meter connected to the sensing means. When the meter records a limiting position, indicating that the load has increased or decreased, to a limiting value, an electrical circuit associated with the meter is operated. This circuit in turn operates adjusting means for the drive of the feeding means whereby the rate of material fed to the compacting means is adjusted. This adjustment is calculated to maintain the energy level and product quality at desired values.

10 Claims, 7 Drawing Figures PATENTED I 3. 24.054 SHEET 1 OF 2 FIGOl E C TRIC CONTROLLER cons TA NT SPEED AND cmvsm N 7 DISPLACEMENT SCREW RPM A P HYDRAULIC PUMP PATENTED JUL 1 6 I974 SHEET 2 UF 2 Mom/2 PRESS DP Vf HYD M070 OIL SUMP DRIVE/MOTOR -1 CONTROLLER FOR COMPACTING MACHINES This invention relates to a compacting apparatus wherein material is fed to compacting means and is thereby compressed into a more dense condition. A typical application of the features of this invention is a briquetting machine wherein material is fed between a pair of compacting rolls, the rolls defining pocketsserving to shape the material into individual briquets.

In briquetting operations as well as in other compacting operations, some type of positive feeding means is preferably employed. For example, a feed screw will convey material to the area of compacting rolls, and the screw design may be such that compression of the material will occur prior to entry of the material between the rolls. An example of an apparatus of this type may be found in Komarek, et al. US. Pat. No. 2,977,631.

Means have been developed for controlling the feed screw operation, for example as described in the aforementioned Komarek, et al. patent. Harris US. Pat. No.

3,674,397 also discusses control systems which can be effectively utilized for purposes of achieving efficient operation of a compacting apparatus. Generally speaking, the control means detect a condition of the operation such as roll spacing or the load on the roll drive motor, and this information is then used for controlling the operation of the feeding mechanisms utilized for delivering material to the compacting rolls.

It is a general object of this invention to provide an improved material compacting construction which in cludes control means adapted to provide optimum product quality in the operation of the system.

It is a 'further object of this invention to provide a control means of the type described which detects changes in the condition of compacting means in a very rapid fashion, and which uses the information detected for purposes of increasing the operating efficiency of the system.

It is a still further object of this invention to provide control means of the type described which are relatively uncomplicated in design so that the control means can be associated with compacting equipment at minimum expense.

These and'other objects of this invention will appear hereinafter and for purposes of illustration, but not of limitation, specific embodiments of the invention are shown in the accompanying drawings in which:

FIG. 1 is an elevational view, partly in section, of a briquetting machine of the type suitable for incorporation of the control means of this invention;

FIG. 2 is a schematic perspective view of the construction;

FIG. 3 is a graphical illustration of certain operating characteristics of control means of the construction functioning in accordance with the teachings of the invention;

FIG. 4 is a graphical illustration of additional operating features of the construction;

FIG. 5 is a schematic circuit diagram illustrating certain operating features of this invention;

FIG. 6 is a schematic circuit diagram illustrating the details of a switching arrangement suitable for use with the construction of the invention; and,

FIG. 7 is a schematic illustration of the concepts of the invention as applied to a hydraulic motor utilized for driving a feed screw.

The construction of the invention is applicable to a compacting means including a drivemeans and a feeding means fordelivering material to the compacting means; The invention is particularly concerned with a control system which includes means for sensing the load on the drive for the compacting means. The system then utilizes this information for controlling the operation of a second drive employed for operating the feeding means.

In addition to the sensing means which are included in the control system, the invention provides for the use of a meter having an operating element such as an indicator needle which moves in response to changes in the condition sensed. Thus, where the sensing means is detecting the load on the drive for the compacting means, the operating element will vary in position as the load varies.

At least one contact is positioned for engagement by the meter needle or some other operating element which is movable in response to the condition sensed. This contact is included in a circuit which includes means for adjusting the vdrive for the feeding means. In a preferred form of the invention, the circuit includes a time delay relay which is activated when the meter needle engages a contact. This relay then operates the adjusting meansfor the drive of the feeding means with the degree of adjustment being determined by the time setting of the relay. Thus, the relay is preferably provided with mechanisms which permit adjustment so that each apparatus provided with a control system of the invention can be operated in a fashion most efficient for that apparatus.

In order to increase the utility of the system, manual adjustment of the drive for the feeding means is preferably provided. In accordance with the invention, thismanual adjustment can be readily incorporated with the time delay relay with the simple operation of a switch permitting movement from automatic to manual operation of the system.

The invention will be described with reference to a briquetting apparatus, however, it will be understood that other compacting structures employing material feedmeans can be modified to include a control system of the type contemplated by the invention. Referring to FIG. 1, a briquetting apparatus 10 is illustrated. This apparatus includes a material feed hopper 12 and feed screw 14. The feed screw operates to deliver material to the nip of briquetting rolls l6 and 18. These rolls define pockets 20 which determine the configuration of the briquetted product.

The briquetting rolls are mounted for rotation within displaceable bearing blocks 22. These blocks are supported within a frame 24 which also carries springs 26. The springs urge the bearing blocks inwardly against adjusting bolts 28. These bolts control the minimum spacing between the rolls, and the springs 26 permit an I increase in this spacing in the event that an over-load condition should occur.

As schematically illustrated in FIG. 2, the hopper 12 receives material through inlet 30, and the feed screw 14 drives this material toward the rolls through operation of motor 32. means of motor 34. An electric controller 36 is connected by means of lines 38 to the feed drive motor 32 and by lines 40 to the roll drive motor 3 FIG. 5 illustrates a typical circuit arrangement for the electric controller and the associated components. The

The briquetting rolls are driven by roll drive motor 34 is connected to a power source through lines 42, and the operation of this motor is controlled by switches 44. Step down transformer mechanisms 46 are utilized for detecting the amperage applied to the press drive motor which provides an accurate indication of the load on the motor. The lines 40 feed the resulting signal to the controller 36.. In order to eliminate operation of the controller as a result of short duration surges in current, a time delay relay 48 may be included in one line 40 so that the signal will be applicable to the controller only if a measurable change in amperage is maintained for a significant period. In a typical system, the time delay relay will be set'to transmit a signal which is maintained for at least seconds.

A coil 50 serves to move needle 52 in response to current changes. This arrangement may comprise a conventional unit, for example a DArsonval movement of the type incorporated in a Simpson API meter relay manufactured by the Simpson Electric Company. In such meters, a pair of contacts 54 are located on opposite sides of the needle, and these contact positions are adjustable so that the range of meter movement can be controlled.

The respective contacts 54 are included in circuits for energizing time delay relays 56 and 58. Thus, when the needle 52 engages one of the contacts 54, a relay coil operates to close a relay switch. FIG. 6 schematically illustrates relay 58 including switch 60 which is closed upon engagement of the needle 52 with the right-hand contact 54.

The switch 60 is included in a circuit also including double pole switch 62 which is connected through line 64 to positioner motor 66. This positioner motor may be, for example, a Reeves type drive positioner motor which controls the operation of feed screw motor 32.

The time delay relay 56 is connected through line 68 and double pole switch 70 to the positioner motor 66. The time delay relays 56 and 58 will be selectively operated depending upon which of the contacts 54 are en I gaged by the needle 52. It will be appreciated that when sensed. Assuming that the decrease is substantial in The circuit illustrated in FIG. 5 is set for automatic operation with the switches 62 and 70 in the positions shown. As indicated, however, these switches are mov- 4 able to positions providing for manual operation, and this condition is illustrated in FIG. 6. The manual operation is accomplished when the circuit including pushbutton switch 72 located in line 74 is completed. The line 74 by-passes the relay switch 60 and, accordingly, the positioner motor 66 can be operated by simply engaging pushbutton 72.

The manual operation is of particular advantage when initially setting the controller. To accomplish this, the switches 62 and are moved to the manual position, and the press is started. The feed screw speed is increased as desired by engaging pushbutton switch 76, and decreased as desired by engaging the counterpart pushbutton switch 72. When the proper speed is achieved, this speed will be maintained until variations thereof occur after the switches 62 and 70 are placed in the automatic position.

The set points for the meter are best determined by experimentation. When the proper feed screw speed has been determined as indicated above, the meter needle 52 can be located in a central position on the scale by means of an appropriate instrument adjustment, and the set points 54 positioned on opposite sides thereof. It has been found that set points between 5 and 10 percent higher and lower than the setting for normal oper ation provide a good practical operation.

The adjustment of time delay relays 56 and 58 is also best determined for each application. In a typical operation, the relay switches will be held closed for from I to 10 seconds so that the positioner motor will operate for a period sufficient to make an effective adjustment in the feed screw speed. It will be appreciated that without a time delay, the needle 52 would back away from a contact almost instantaneously so that the positioner motor would have only a very short operating time. The tendency would then be for the needle to repeatedly engage the contact which would, of course, provide an inefficient operation.

In some instances for example operations involving low press roll speed and/or low'feed screw speed, the press drive amperage and, accordingly, the meter indications tend to fluctuate with each feed screw revolution. The flucutation may be greater than the 5 to 10 percent preferred settings of the meter setpoints; however, the fluctuations are not true indications of changes in the condition of the material being fed. To avoid repeated operation of the positioner motor, the

time delay relays 56 and 58 may be of the type having a tum-on delay period as well as a turn-off delay period. Such relays can be set so that the needle 52 must be continuously held against a contact 54 for a matter of a few seconds before the relay coil will energize to close the relay switch. If the needle backs away from the contact before this initial delay period, then the positioner motor will not be operated.

FIG. 7 illustrates an application of the invention to a system employing a hydraulic motor for driving feed screw 82. In this system, the load condition of compacting rolls 84 is sensed, and the controller 86 operates in accordance with fluctuations in amperage in the manner previously described.

The output of controller 86 is applied to a positioner motor 88 which is connected to by-pass valve 90. Hydraulic fluid for driving motor 80 is passed through lines 92 and 94, and the valve is included in line 96 whereby the condition of valve 90 will affect the feed to motor 80. Thus, the hydraulic pump 98 may be a constant displacement pump; however, the feed to motor 80 can be varied by opening and closing valve 90, and the positioner motor 88 will accomplish these opening and closing operations in accordance with the fluctuations on the load on the compacting rolls.

FIGS. 3 and 4 illustrate graphically the varying operating conditions of hydraulic systems including control mechanisms of the type contemplated by the invention. In FIG. 3, the change in horse power as affected by changes in the screw RPM isillustrated. FIG. 4 illustrates the horse power changes in accordance with changes in hydraulic pump pressure. By charting the conditions in this manner, the system of the invention provides a highly simplified means for determining the best operating conditions for a given compacting operanon.

It will be understood that various changes and modifications may be made in the above described construction which provide the characteristics of the invention without departing from the spirit thereof, particularly as defined in the following claims.

That which is claimed is:

1. In a material compacting construction comprising a compacting means including rolls, a first drive for continuously operating the compacting means, a feeding means for continuously delivering material to the compacting means comprising a screw delivering said material under pressure to said compacting means, and a second drive for the feeding means, the improvement in control means for operating said second drive, said control means comprising means for sensing the load on said first drive, a meter connected to said sensing means, a movable operating element associated with said meter for movement in response to said sensing means, a pair of contacts engageable by said operating element, means for adjusting the operation of said second drive comprising a positioner motor connected to.

said second drive for varying the operating speed of said second drive, one of said contacts being included in a circuit operating said adjusting means to increase the speed of said second drive and the other of said contacts being included in a circuit operating said adjusting means to decrease the speed of said second drive, and means connecting the adjusting means to said contacts whereby engagement of said contacts by said operating element operates said adjusting means.

2. A construction in accordance with claim 1 wherein said operating element comprises a conductive needle,

an electrical circuit including said needle, and means in said circuit operable upon engagement of said needle with said contact for operating said adjusting means.

3. A construction'in accordance with claim 1 wherein said operating element comprises a conductive needle, an electrical circuit including said needle extending to time delay means for operating said time delay means upon engagement of said needle with'said contact, said delay means being connected to said adjusting means for operating the adjusting means, and means for setting said time delay means to maintain the operation of the adjusting means for a predetermined time following the engagement of said needle with said contact.

4. A construction in accordance with claim 3 wherein said time delay means comprises a relay, and means for adjusting the time of operation of the relay for thereby varying the time of operation of said adjusting means.

5. A construction in accordance with claim 3 including means for excluding time delay means from said circuit, and manually operable switch means for operating said adjusting means when said time delay means is excluded from said circuit.

6. A construction in accordance with claim 1 wherein said second drive comprises an electrical motor.

7. A construction in accordance with claim 1 wherein said second drive comprises a hydraulic motor, said positioner motor being connected to a variable position valve connected in the line passing hydraulic fluid used for driving the hydraulic motor.

8. A construction in accordance with claim 1 wherein said compacting means comprise briquetting rolls, and wherein operation of said adjusting means controls the rate at which material is fed to said rolls by said feeding means.

9. A construction in accordance with claim 3 wherein said time delay means comprises a time delay relay, and including means for delaying the energization of the relay coil until said needle continuously engages one of said contacts for a predetermined period of time.

10. A construction in accordance with claim 3 including an additional time delay means extending between said sensing means and said meter, said additional time delay means preventing fluctuations in said meter needle until said sensing means continuously detects a variation in said load for a predetermined period oftime. 

1. In a material compacting construction comprising a compacting means including rolls, a first drive for continuously operating the compacting means, a feeding means for continuously delivering material to the compacting means comprising a screw delivering said material under pressure to said compacting means, and a second drive for the feeding means, the improvement in control means for operating said second drive, said control means comprising means for sensing the load on said first drive, a meter connected to said sensing means, a movable operating element associated with said meter for movement in response to said sensing means, a pair of contacts engageable by said operating element, means for adjusting the operation of said second drive comprising a positioner motor connected to said second drive for varying the operating speed of said second drive, one of said contacts being included in a circuit operating said adjusting means to increase the speed of said second drive and the other of said contacts being included in a circuit operating said adjusting means to decrease the speed of said second drive, and means connecting the adjusting means to said contacts whereby engagement of said contacts by said operating element operates said adjusting means.
 2. A construction in accordance with claim 1 wherein said operating element comprises a conductive needle, an electrical circuit including said needle, and means in said circuit operable upon engagement of said needle with said contact for operating said adjusting means.
 3. A construction in accordance with claim 1 wherein said operating element comprises a conductive needle, an electrical circuit including said needle extending to time delay means for operating said time delay means upon engagement of said needle with said contact, said delay means being connected to said adjusting means for operating the adjusting means, and means for setting said time delay means to maintain the operation of the adjusting means for a predetermined time following the engagement of said needle with said contact.
 4. A construction in accordance with claim 3 wherein said time delay means comprises a relay, and means for adjusting the time of operation of the relay for thereby varying the time of operation of said adjusting means.
 5. A construction in accordance with claim 3 including means for excluding time delay means from said circuit, and manually operable switch means for operating said adjusting means when said time delay means is excluded from said circuit.
 6. A construction in accordance with claim 1 wherein said second drive comprises an electrical motor.
 7. A construction in accordance with claim 1 wherein said second drive comprises a hydraulic motor, said positioner motor being connected to a variable position valve connected in the line passing hydraulic fluid used for driving the hydraulic motor.
 8. A construction in accordance with claim 1 wherein said compacting means comprise briquetting rolls, and wherein operation of said adjusting means controls the rate at which material is fed to said rolls by said feeding means.
 9. A construction in accordance with claim 3 wherein said time delay means comprises a time delay relay, and including means for delaying the energization of the relay coil until said needle continuously engages one of said contacts for a predetermined period of time.
 10. A construction in accordance with claim 3 including an additional time delay means extending between said sensing means and said meter, said additional time delay means preventing fluctuations in said meter needle until said sensing means continuously detects a variation in said load for a predetermined period of time. 